Safety And Efficacy Of Axitinib (Axi) In Combination With Pembrolizumab (Pembro) In Patients (Pts) With Advanced Renal Cell Cancer (Arcc).

579Background: Prior studies combining programmed death-1 (PD-1) checkpoint inhibitors with tyrosine kinase inhibitors of the vascular endothelial growth factor (VEGF) pathway have been characterized by excess toxicity precluding further development. We hypothesized that a combination of axi, a more selective VEGF-pathway inhibitor, with pembro (anti-PD-1) would be well tolerated and yield antitumour activity in treatment-naive pts with aRCC. Methods: This ongoing open-label phase Ib study of axi/pembro comprised a dose-finding phase to determine the maximum tolerated dose and dose expansion phase. Axi 5 mg was administered orally twice daily with pembro 2 mg/kg administered intravenously every 3 weeks. Tumors were assessed, using RECIST v1.1, at baseline, week 12, and every 6 weeks thereafter. The primary endpoint was dose-limiting toxicity (DLT) during the first 2 cycles (6 weeks), with secondary endpoints evaluating safety, objective response rate (ORR), progression-free survival (PFS), and overall sur...